1. Field of the Invention
The present invention relates to a chip, a multichip module, and an apparatus provided with the same, and particularly relates to a multichip module in which a plurality of semiconductor chips is mounted on a mounting board.
2. Description of the Related Art
Japanese Patent Application Laid-Open No. H11-112728 discloses a contact type image sensor in which components such as a plurality of sensor chips, an amplifier chip, a capacitor and a resistor are mounted on the same board. It is described that the amplifier chip and the sensor chip are mounted on the same board, and thereby can reduce the volume of the module or a unit, due to the configuration. Furthermore, it is also described that a voltage in a reset state is clamped and is used as a reference signal, and thereby a fixed pattern noise (FPN) due to a step between chips is removed.
In the multichip module such as the contact type image sensor described in Japanese Patent Application Laid-Open No. H11-112728, wires which connect chips to each other have a parasitic capacitance between the wire and another wire or the ground. When a signal which is transmitted between the chips is a voltage signal, the variation of the voltage when the signal is transmitted and received between the chips causes charging and discharging of the parasitic capacitance, and a power supply voltage fluctuates. This fluctuation of the power supply voltage varies a reference potential in the chip, and accordingly the above described variation of the signal voltage can become a cause of the noise.